Can i be pregnant

My husband and i had sex July 31 it was one of my fertile days he think he pre cum in me im not in any birth control the next day was my ovulation three week later im getting early pregnancy sign im getting nausea, with my other pregnancy if i brush my teeth with a certain toothpaste i will get nausea i dont know if im over thinking it or I might be pregnant i will get my period in 7 days but can i be pregnant or is it to soon to tell